HistoryThe following is taken from New York in the War of the Rebellion, 3rd ed.
Frederick Phisterer. Albany: J. B. Lyon Company, 1912.

Left the State in detachments: 1864
Mustered out: June 27,1865

September 4, 1863, Col. Henry F. Liebenau received authority from the Governor
of the State to recruit a regiment of cavalry, which, January 15, 1864, received
the above numerical designation. It was organized at Saratoga Springs and
Hart's island, under Colonel Liebenau, and his successor, Col. Gurden Chapin,
for a service of three years; Companies I and M, however, contained a few
men enlisted for but one year. The companies were mustered in the service
of the United States at Saratoga, A and B February 20; C and D March 19;
E and F April 14 and 23, respectively; at Hart's island, G April 20; H July
29; I September 18; K May 16, and L and M October 15 and 20, 1864, respectively.

The companies were recruited principally; A at Hancock, Saratoga Springs,
Fremont and Greene county; B at Hancock, Root, Fremont and Stillwater; C at
New York
city, Neversink, Goshen, Saratoga, Half moon and Montgomery; D at Saratoga,
Montgomery, New York city, Schenectady and Root; E at Saratoga, Goshen, Kingston
and New York city; F at Saratoga and New York city; G and K at New York city;
H at New York city, Brooklyn, Williamsburg, Goshen and Watertown; I at New
York city, Brooklyn, Alberg, Goshen, Jamaica, Poughkeepsie, Tarrytown and
Troy; L and M at New York city, Brooklyn, Jamaica, Goshen, Kingston, Plattsburg,
Tarrytown, Troy and Schenectady.

The regiment left the State in 1864, by detachments, and served in the defenses
of Washington, D. C., 22d Corps, from April, 1864; in the Provost Guard,
Army of the Potomac, from June, 1864; at Washington, D. C., 22d Corps,
from July
7, 1864; in the 4th Brigade, 1st Division, Cavalry, Army of Potomac, from
August, 1864; in the 1st Brigade, 1st Division, Cavalry, from September,
1864; in the
Army of the Shenandoah from October, 1864, and in the Cavalry Division,
Army of West Virginia, from April, 1865.

Commanded by Lieut.-Col. Aaron Seeley, the regiment
was honorably discharged, and mustered out, June 27, 1865, at Hart's island,
New York harbor, having, during its service, lost by death, killed in action,
1 officer, 10 enlisted men; of wounds received in action, 6 enlisted men; of
disease and other causes, 49 enlisted men; total, 1 officer, 65 enlisted men;
aggregate, 66; of whom 7 enlisted men died in the hands of the enemy.

Further ReadingThis is meant to be a comprehensive list. If, however, you know of a resource that is not listed below, please send an email to ng.ny.nyarng.list.historians@mail.mil with the name of the resource and where it is located. This can include photographs, letters, articles and other non-book materials. Also, if you have any materials in your possession that you would like to donate, the museum is always looking for items specific to New York's military heritage. Thank you.

Proceedings of the third annual reunion of the 25th N.Y.
vet cavalry ass'n held in New York city, Sept. 20, 1893.